A cone crusher is used for crushing materials such as rocks, stones and ores. A typical cone crusher has a conical body arranged to rotate eccentrically with respect to a concave element mounted on an upper frame. The eccentric rotation of the conical body with respect to the concave element means that gap between the body and concave element opens and closes, thus crushing material therebetween.
It will be appreciated that the outside surface of the conical body and the inside surface of the concave element can be subject to high levels of wear during use of the crusher. To combat the high levels of wear, the outer surface of the conical body and/or the inside surface of the concave element are replaceable or provided with a sacrificial lining.
FIG. 1 shows a cone crusher 110 of the prior art. A conical mantle 112 is positioned over a conical body 114 of the cone crusher. The mantle 112 is clamped to the conical body using a single nut 116, which engages a large diameter cylindrically shaped neck 118 at the upper end of the conical body. When the nut 116 is tightened, it presses the mantle 112 into compressive engagement with the conical body 114.
During operation of the cone crusher, the conical body 114 rotates eccentrically, so as to crush material between the mantle 114 and a lining of the concave cover. However, contact with material to be crushed (e.g. a rock or a stone) may cause the mantle 112 to temporarily stop rotating or to temporarily rotate slower than the conical body 114. Such relative rotational motion can cause relative rotation between the nut 116 and the conical body 114, resulting in the nut 116 becoming loosened from the conical body 114.
To prevent the nut 116 being loosened from the conical body 114 by this movement, the thread on the nut 116 is provided in a direction such that the nut 116 tightens during operation rather than loosens. Nevertheless, prior to operation of the cone crusher, the nut 116 must be securely tightened onto the conical body 114. This requires considerable torque and typically this can only be applied by the use of a sledge hammer, which can have safety implications.
FIG. 6 shows an upper frame assembly of a known cone crusher, having a concave element 150 with a sacrificial liner 152. The liner 152 has lugs 154 that are configured to overlap a portion of the concave element 150. The liner 152 is jacked into engagement with the cover 150 using wedges 156 between the lugs 154 and the cover 150. Positioning the wedges is a physically exerting task which often requires the use of a T-bar and a sledge hammer, and thereby raises safety issues.